Direct CombinationDirect Combination
Printable Version of this PageHome PageRecent ChangesSearchSign In

DC in a nutshell

A quick guide to Direct Combination

Role-based Infrastructure

  • The original CHI paper CHI99DC.pdf is fun, and a good read, and is recommended, but it is important to realise that the framework and programming mechanisms are completely different in the version from 2002 onwards. The original implementation based on class based decomposition and inheritance mechanisms proved too brittle to allow DC to be really flexible, but the change to a role-based system in 2001/2002 transformed what was possible. N-fold interaction and viewpoints became simple, and user-driven incrementally-developed systems became straightforward.

Universal Composition

  • Improved mechanisms were made possible by ideas from the late Henrik Gedenryd's Universal Composition - a radical new way of organising computational objects. Henrik was adamant that this could make viewpoints easier. Simon Holland worked out a mechanism to re-conceptualise and implement n-fold Direction Combination in a scaleable fashion. Simon noticed that Universal Composition was conceptually isomorphic to Trigve Reyskaug's work on OORAM. To find out more about these mechanisms look at "Meeting the software engineering challenges of interacting with dynamic and ad-hoc computing environments" Dynamic and ad-hoc.pdf, and OOPSLA OOPSLA 2004 RC Holland Final.pdf.